In order to qualify for substantial tax exemptions, nonprofit hospitals must provide certain types of community benefit in the jurisdictions they serve. Due to specific requirements associated with the Affordable Care Act (ACA) and the Internal Revenue Service (IRS), as well as changing market conditions, it is anticipated that a significant portion of hospital community benefit expenditures will shift from charity care toward other activities. There are vast resources at stake, an excess of $60 billion annually is currently spent on community benefit activities and there is tremendous potential for those resources to serve an important role in integrating healthcare and public health infrastructure. Our proposed research targets a critical need to understand (1) how hospitals fulfill their community benefit requirements, (2) the ways in which hospital community benefit activities evolve in response to the ACA, (3) what factors facilitate authentic engagement with community and public health infrastructure by nonprofit hospitals, and (4) which community benefit activities are effective at improving the population health and well-being. We propose an iterative mixed quantitative and qualitative approach. The findings that emerge from the quantitative study will inform the design and sample of the qualitative study. The information generated in the qualitative study will be tested quantitatively to assess their generalizability to other hospitals and market areas. The ultimate goal is to develop evidence-based recommendations for hospital administrators and policy-makers about best practices with the goal of increasing the effectiveness of community benefit spending to improve population health and well-being. The quantitative study is focused on analyzing the shift from uncompensated/charity care spending to the multitude of ways in which nonprofit hospitals respond to the changing community benefit landscape. We propose to apply econometric techniques to analyze pre- and post-ACA changes in the type and magnitude of spending by comparing pre-post changes in spending by hospitals in states that expanded Medicaid to those that did not expand Medicaid. This approach will be used to identify and characterize the substitution between types of spending and assess the degree that spending is responsive to local market needs. Our primary data sources include (1) IRS tax filings that provide qualitative and quantitative detail on the type and amount of community benefit spending and (2) hospital financial data from the Centers for Medicare and Medicaid Services (CMS) Hospital Cost Report Information System (HCRIS). The results will also be used to identify dynamic systems and hospitals for in-depth qualitative interviews. The qualitative analysis will identify innovative models and approaches to community benefit activities. This analysis is critical to understanding ways in which nonprofit hospital community benefit activities improve the health and well-being of the populations they serve. This knowledge will be useful to nonprofit hospitals and policy-makers at all levels as they consider potential alternative avenues for expending community benefit dollars.